We propose ShearSheet, a low-cost, feasible, and simple DIY method that enables tangential (shear) force input on a touchscreen using a rubber-mounted slim transparent sheet. The sheet has tiny conductive material(s) attached to specific positions on the underside so that displacement of the sheet is recognized as touch input(s). This allows the system to distinguish between normal touch input and shear force input depending on whether the sheet moves or not, without requiring any external sensors or power. We first introduce ShearSheet's simple implementation for a smartphone and then discuss several promising interaction techniques that augment shear interaction with one- and two-finger operations. We demonstrate the effectiveness of ShearSheet's smooth transition between position- and rate-based control through a controlled user study using simple scrolling tasks. The results confirm that ShearSheet offers improved performance such as fewer operations and higher subjective preference, suggesting its substantial benefits and potential applications.